The present invention relates to calorimetric equipment, and in particular, to equipment for measuring the product of temperature change and fluid flow rate around a heat dissipating load.
It is known to make a calorimetric measurement by measuring the temperature change in a fluid flowing past a heat dissipating load. The heat rate is proportional to the flow rate multiplied by the temperature difference. For example, in the broadcast industry a power measurement is often performed by enclosing a special resistor in a water conduit. The equipment includes temperature sensors and flowmeters to allow direct measurement of the flow rate and temperature change. A typical measurement process involves calculating the power when the energy to the load is increased to represent 80, 100 and 110 percent of the rated power for the broadcast transmission. When the power is set at these points, a meter ordinarily used to measure power can then be accurately calibrated for these set points.
A disadvantage with this type of calibration procedure is the relatively long time required to manually adjust power and then to calculate power dissipation. Another disadvantage is that these systems must be operated carefully so that power is not placed into a load while the water is stagnant. Otherwise, the relatively expensive load impedance can be quickly burned out.
It is known to construct power meters with thermocouples so that the power can be measured as a function of the heat generated. However, these apparatus have not been designed for relatively high power applications where a flowing fluid must conduct away excess test.
Accordingly, there is a need for a precise and simplified technique for calibrating and measuring power.